Today, there is lighting control for indoor lighting devices performed by means of an illumination controller which detects the level of light in the premises and controls the light output level of a set of lighting devices accordingly, wherein the light output level of the set of lighting devices is set in dependence of the detected level of the illumination. The purpose is to save energy by minimizing the level of illumination provided by the controlled lighting device while still obtaining a desired total illumination within the area which is covered by the set of, i.e. one or more, lighting devices. However, it would be advantageous to be able to discriminate the detected light in daylight and artificial light in a simple way.